I think the strongest clue to whether your property is gold bearing lies in its history. Was there any activity on what is now your property back in the gold rush days when hundreds and thousands of prospectors moved through the districts? Is there any evidence of old test holes or surface diggings in gullies or on top of hills? Here I would note that the old timers would probably have started their sampling in or alongside creeks as a first indicator of whether the hills were shedding gold - that you have no creek to speak of might suggest the old timers did not stop there to prospect, but instead moved on to where there was some water.
Unless your property lies in what was a proclaimed goldfield, I think you would be unlikely to find historical information on sites such as
trove.nla.gov.au that give a really good insight to the gold rush era.
If there is no historical evidence to show your property was gold bearing does not necessarily mean there is no gold there ... but on the other hand it does suggest there was not any worthwhile gold there, at least in the eyes of the old timers.
To find out today whether your property is gold bearing requires the same approach as the old timers ... sample, sample, sample, using geology and topology as your guides. 3,000 acres is a large area to cover, so you must be selective. The lowest lying gullies might be a starting point - see if there any which are holding gravels rich with ironstone and/or quartz. If there is any gold in the hills on your property, it is most likely there should be evidence of alluvial gold in the gullies that make way down towards a creek.
If you wish to swing a detector on the hills, look for areas where there is ironstone and/or quartz on the surface. In particular look for trees with quartz pebbles scattered around their base. These are suggestive indicators only and do not necessarily mean there is gold there. At the end of the day, gold is where it is.
Just my thoughts, noting I am no expert - but I am in a similar situation of having 3,000 acres of family farm in a gold-bearing country. Only differences are that I have a creek which was prospected in the gold rush era, and our property lies in a proclaimed gold field with lots of historical literature to guide me.